As automobile technology has advanced through the years, a variety of automobile systems have been improved to take advantage of technological innovations. Crank-operated windows have given way to motor-driven windows, manual brakes have given way to power brakes and, more recently, to anti-lock braking mechanisms, advanced cruise control mechanisms now supplement the accelerator and brake pedals and a variety of other convenience-enhancing improvements have been implemented. However, certain controls have remained unchanged for almost half a century. The directional indicator, more commonly termed the "turn signal", for example, utilizes a control is essentially the same mechanism that was introduced several decades ago.
Such a turn signal control is shown in FIG. 1 which details the driver's side of a conventional automobile passenger compartment 20. A steering wheel 24 mounted on a steering column 26 is shown along with an instrument cluster 28, dashboard 30, windshield 32 and center console 34. The turn signal is controlled by a steering column-mounted control stalk 36 that moves pivotally upwardly and downwardly as depicted by the arrow 38.
The control stalk 36 actuates a set of mechanical switches (not shown) inside the steering column 26 so that upward (clockwise) movement causes a right turn signal switch to be activated and downward movement (counterclockwise) causes a left turn signal switch to be activated. When a given switch is activated, it closes a circuit on a flasher unit comprising, generally, a bimetallic switch that alternately opens and closes the circuit in order to provide a reciprocating on/off current to front and rear exterior turn signal marker lights (not shown). The circuit also includes, typically, one or two dashboard mounted indicator lights 40 and 42 that flash in conjunction with the exterior marker lights. In this example, a left hand indicator light 40 and a right hand indicator light 42 are located on opposite sides of the instrument cluster 28. Each indicator light 40 and 42 flashes independently when a given turn is indicated and usually takes the form of an arrow symbolizing the corresponding turn direction.
The conventional control stalk 36 depicted in FIG. 1 is constructed so that it remains in an upward or downward actuated position (thus, activating a respective set of exterior turn signal marker lights) until it is returned to the neutral, center or "off" position (as shown). Like virtually all modern automobile steering columns, this column 26 is contemplated as being mechanically interconnected with the turn signal control stalk, so that, the stalk is automatically returned to neutral after a turn is completed. In conducting a vehicle turn, a driver typically places the turn signal into one of its actuated positions to signal either a left or right turn. The driver then turns the steering wheel 24 to cause the vehicles front wheels (not shown) to point in the direction of the turn. The turn signal control stalk 36 is interconnected in such a manner that the turning of the steering wheel 24 into the turn does not affect the actuation of the turn signal control stalk 36. However, as the turn is completed, and the wheel 24 returns to a "straight" steering orientation, a return linkage (not shown) within the steering column 26 forces the control stalk 36 back into a neutral position, thus deactivating the turn signal.
The mechanical interconnection between the turn signal control stalk 36 and the steering column 26 is generally effective for wide turns. However, narrower turns, or lane changes do not typically require a sufficient enough rotation of the steering wheel 24 to activate the return linkage and, thus, the signal control stalk 36 remains in an actuated, or "on", position until manually brought back to neutral. A particular disadvantage of such a system is that drivers may not always be aware that the turn signal is still in operation after completing a maneuver. As such, the continuing operation of the turn signal may pose a danger to other drivers who cannot accurately determine or predict whether the vehicle intends to perform further turning maneuvers. This problem is particularly exacerbated in high speed highway driving situations.
Additionally, over time, the mechanical interconnection between the turn signal control stalk 36 and the steering column 26 may wear, thus preventing reliable return of the control stalk 36 to its neutral, or "off", position, following even sharp turns.
In view of the disadvantages of a conventional turn signal control design, it is an object of this invention to provide a turn signal control with more reliable shut-off even after shallow turns. It is a further object of this invention to provide a turn signal control that is less prone to mechanical wear over time and exhibits increased reliability. Such a turn signal control should also be ergonomically designed to provide greater ease of use.